scholarly journals Juvenile hormone regulation on the flight capability of Bactrocera dorsalis (Diptera: Tephritidae)

2019 ◽  
Author(s):  
Peng Chen ◽  
Min Chen ◽  
Hui Ye ◽  
Ruiling Yuan ◽  
Chunhua Du ◽  
...  

AbstractThe oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is considered a major economic threat in many regions worldwide. In order to better understand the flight capacity of B. dorsalis and its physiological basis, the functions and regulatory roles of juvenile hormone (JH) in the flight muscle of B. dorsalis were studied under a controlled environment. JH titer of B. dorsalis varied with age and sex. Females, irrespective of age, have higher JH than males for ovarian development and maturation in addition to better flight capabilities. The flight duration and distance of both males and females increased with the gradual increase of JH titer after adult emergences. JH titer peaked in 15-d-old adult and declined subsequently with age. Flight activity stimulated the production of JH as adults flown for 24 hours on the flight mills have the highest JH titers compare to adults tethered on shorter flight durations. Furthermore, JH III-treated adults were able to perform long-duration and long-distance flights. The mutual reinforcement of JH and flight activity provides fundamental understanding on the physiological aspects of the flight capability and dispersal, which facilitates strategies for the long-term control of this destructive pest.

2017 ◽  
Vol 107 (6) ◽  
pp. 715-723 ◽  
Author(s):  
X.-W. Fu ◽  
H. Chang ◽  
L.-M. He ◽  
S.-Y. Zhao ◽  
K.-M. Wu

AbstractMacdunnoughia crassisigna Warren (Lepidoptera: Noctuidae) is a highly destructive herbivore that poses a serious risk to cotton, maize, soybean, and cruciferous vegetables in East Asia. Examining the effects of various biotic and abiotic factors on the flight performance of M. crassisigna is crucial for a better understanding of its trans-regional migration. In this study, the flight activity of M. crassisignai moths of different ages, under different temperatures and relative humidity (RH) levels, was evaluated by tethering individuals to computerized flight mills for a 24-h trial period. The results showed that M. crassisignai had the capacity for sustained flight and the flight ability was strongest in 3-day-old individuals, and then their flight performance decreased significantly in older moths. For both sexes, temperature had a significant effect on their flight performance, and the flight activity was relatively higher at 24–28°C than other temperatures. There was a significant effect of RH on all flight parameters of the tested moths, and the flight activity was relatively higher at RH of 60–75% than other RH levels. For 3-day-old moths under the optimum conditions (24°C and 75% RH) throughout the 24 h scotophase, their mean flight distance reached 66 km, and the mean flight duration reached 13.5 h, suggesting M. crassisigna possess strong potential to undertake long-distance migration. These findings will be helpful for developing sound forecasting systems of this pest species.


2020 ◽  
Author(s):  
Roy Faiman ◽  
Alpha Seydou YARO ◽  
Moussa Diallo ◽  
Adama Dao ◽  
Djibril Samake ◽  
...  

Abstract Background In the West African Sahel, mosquito reproduction is halted during the 5-7 month-long dry season, due to the absence of surface waters required for larval development. However, recent studies have suggested that both Anopheles gambiae sensu stricto (s.s.) and Anopheles arabiensis repopulate this region via migration from distant locations where larval sites are perennial. Anopheles coluzzii engages in more regional migration, presumably within the Sahel, following shifting resources correlating with the ever-changing patterns of Sahelian rainfall. Understanding mosquito migration is key to controlling malaria—a disease that continues to claim more than 400,000 lives annually, especially those of African children. Using tethered flight data of wild mosquitoes, the distribution of flight parameters were evaluated as indicators of long-range migrants versus appetitive flyers, and the species specific seasonal differences and gonotrophic states compared between two flight activity modalities. Morphometrical differences were evaluated in the wings of mosquitoes exhibiting high flight activity (HFA) vs. low flight activity (LFA).Methods A novel tethered-flight assay was used to characterize flight in the three primary malaria vectors- An. arabiensis, An. coluzzii and An. gambiae s.s. The flights of tethered wild mosquitoes were audio-recorded from 21:00h to 05:00h in the following morning and three flight aptitude indices were examined: total flight duration, longest flight bout, and the number of flight bouts during the assay.Results The distributions of all flight indices were strongly skewed to the right, indicating that the population consisted of a majority of low-flight activity (LFA) mosquitoes and a minority of high-flight activity (HFA) mosquitoes. The median total flight was 586 seconds and the maximum value was 16,110 seconds (~4.5 h). In accordance with recent results, flight aptitude peaked in the wet season, and was higher in gravid females than in non-blood-fed females. Flight aptitude was also found to be higher in An. coluzzii compared to An. arabiensis, with intermediate values in An. gambiae s.s., but displaying no statistical difference. Evaluating differences in wing size and shape between LFA individuals and HFA ones, the wing size of HFA An. coluzzii was larger than that of LFAs during the wet season—its length was wider than predicted by allometry alone, indicating a change in wing shape. No statistically significant differences were found in the wing size/shape of An. gambiae s.s. or An. arabiensis.Conclusions The partial agreement between the tethered flight results and recent results based on aerial sampling of these species suggest a degree of discrimination between appetitive flyers and long-distance migrants although identifying HFAs as long-distance migrants is not recommended without further investigation.


2020 ◽  
Author(s):  
Roy Faiman ◽  
Alpha Seydou YARO ◽  
Moussa Diallo ◽  
Adama Dao ◽  
Djibril Samake ◽  
...  

Abstract Background In the West African Sahel, during the 5-7 month-long dry season mosquito reproduction is halted due to the absence of surface waters required for larval development. Recent studies have suggested that both Anopheles gambiae s.s and A. arabiensis persist in this region by migration from distant locations where larval sites are perennial, and A. coluzzii engages in long-distance migration, presumably within the Sahel, following shifting resources due to the ever-changing patterns of Sahelian rainfall. Understanding mosquito migration is key to malaria control, a disease that still kills >400,000 people, mostly children in Africa. Methods We used a new tethered-flight assay to characterize flight in the three primary malaria vectors mentioned above and evaluated seasonal differences in their flight activity. The flight of tethered wild mosquitoes was audio-recorded from 21:00h to 05:00h in the following morning and three flight aptitude indices were examined: total flight duration, longest flight bout, and the number of flight bouts during the assay. Based on recent studies, we predicted that (i) the distribution of the flight aptitude indices would exhibit bi-modality and/or marked skewness, indicating a subpopulation of high flight activity (HFA) associated with long-distance migrants, in contrast to low flight activity (LFA) in appetitive flyers. Additionally, flight aptitude would (ii) increase in the wet season, (iii) increase in gravid females, and (iv) vary among the vector species. ResultsThe distributions of all flight indices departed sharply from a normal curve, and were strongly skewed to the right, consistent with the division of the population into a majority of LFAs and a minority of HFAs, e.g., the median total flight was 586 seconds, and its maximum value was 16,110 seconds (~4.5 h). As predicted, flight aptitude peaked in the wet season and was higher in gravid females than in non-bloodfed females. Flight aptitude was higher in A. coluzzii than in A. arabiensis, but A. gambiae s.s. was not statistically different from either. We evaluated differences in wing size and shape between LFAs and HFAs. During the wet season, wing size of HFA A. coluzzii was larger than that of LFAs; it was wider than predicted by its length, indicating a shape change. However, no statistically significant differences were found in wings of A. gambiae s.s. or A. arabiensis. ConclusionsThe partial agreement between the assay results and predictions suggest a degree of discrimination between appetitive flyers and long-distance migrants. Wing size and shape seems to indicate higher flight activity in A. coluzzii during the wet season.


2020 ◽  
Vol 23 (4) ◽  
pp. 1120-1129
Author(s):  
Peng Chen ◽  
Min Chen ◽  
Hui Ye ◽  
Ruiling Yuan ◽  
Chunhua Du ◽  
...  

2020 ◽  
Author(s):  
Roy Faiman ◽  
Alpha S. Yaro ◽  
Moussa Diallo ◽  
Adama Dao ◽  
Samake Djibril ◽  
...  

AbstractBackgroundIn the West African Sahel, during the 5-7 month-long dry season mosquito reproduction is halted due to the absence of surface waters required for larval development. Recent studies have suggested that both Anopheles gambiae s.s and A. arabiensis persist in this region by migration from distant locations where larval sites are perennial, and A. coluzzii engages in long-distance migration, presumably within the Sahel, following shifting resources due to the ever-changing patterns of Sahelian rainfall. Understanding mosquito migration is key to malaria control, a disease that still kills >400,000 people, mostly children in Africa.MethodsWe used a new tethered-flight assay to characterize flight in the three primary malaria vectors mentioned above and evaluated seasonal differences in their flight activity. The flight of tethered wild mosquitoes was audio-recorded from 21:00h to 05:00h in the following morning and three flight aptitude indices were examined: total flight duration, longest flight bout, and the number of flight bouts during the assay. Based on recent studies, we predicted that (i) the distribution of the flight aptitude indices would exhibit bi-modality and/or marked skewness, indicating a subpopulation of high flight activity (HFA) associated with long-distance migrants, in contrast to low flight activity (LFA) in appetitive flyers. Additionally, flight aptitude would (ii) increase in the wet season, (iii) increase in gravid females, and (iv) vary among the vector species.ResultsThe distributions of all flight indices departed sharply from a normal curve, and were strongly skewed to the right, consistent with the division of the population into a majority of LFAs and a minority of HFAs, e.g., the median total flight was 586 seconds, and its maximum value was 16,110 seconds (~4.5 h). As predicted, flight aptitude peaked in the wet season and was higher in gravid females than in non-bloodfed females. Flight aptitude was higher in A. coluzzii than in A. arabiensis, but A. gambiae s.s. was not statistically different from either. We evaluated differences in wing size and shape between LFAs and HFAs. During the wet season, wing size of HFA A. coluzzii was larger than that of LFAs; it was wider than predicted by its length, indicating a shape change. However, no statistically significant differences were found in wings of A. gambiae s.s. or A. arabiensis.ConclusionsThe partial agreement between the assay results and predictions suggest a degree of discrimination between appetitive flyers and long-distance migrants. Wing size and shape seems to indicate higher flight activity in A. coluzzii during the wet season.


2020 ◽  
Author(s):  
Roy Faiman ◽  
Alpha Seydou YARO ◽  
Moussa Diallo ◽  
Adama Dao ◽  
Djibril Samake ◽  
...  

Abstract Background In the West African Sahel, mosquito reproduction is halted during the 5-7 month-long dry season, due to the absence of surface waters required for larval development. However, recent studies have suggested that both Anopheles gambiae s.s and An. arabiensis repopulate this region via migration from distant locations where larval sites are perennial. An. coluzzii engages in more regional migration, presumably within the Sahel, following shifting resources correlating with the ever-changing patterns of Sahelian rainfall. Understanding mosquito migration is key to controlling malaria—a disease that continues to claim more than 400,000 lives annually, especially those of African children. Using tethered flight data of wild mosquitoes, we evaluated the distribution of flight parameters as indicators of long-range migrants vs. appetitive flyers, compared species specific seasonal differences and gonotrophic states on flight activity. We also evaluated morphometrical differences in the wings of mosquitoes exhibiting high flight activity (HFA) vs. low flight activity (LFA). Methods We used a novel tethered-flight assay to characterize flight in the three primary malaria vectors- An. arabiensis, An. coluzzii and An. gambiae s.s. The flights of tethered wild mosquitoes were audio-recorded from 21:00h to 05:00h in the following morning and three flight aptitude indices were examined: total flight duration, longest flight bout, and the number of flight bouts during the assay. Results The distributions of all flight indices were strongly skewed to the right, indicating that the population consisted of a majority of low-flight activity (LFA) mosquitoes and a minority of high-flight activity (HFA) mosquitoes. The median total flight was 586 seconds and the maximum value was 16,110 seconds (~4.5 h). In accordance with recent results, flight aptitude peaked in the wet season, and was higher in gravid females than in non-bloodfed females. Flight aptitude was also found to be higher in An. coluzzii compared to An. arabiensis, with intermediate values in An. gambiae s.s., but displaying no statistical difference. Evaluating differences in wing size and shape between LFA individuals and HFA ones, the wing size of HFA An. coluzzii was larger than that of LFAs during the wet season—its length was wider than predicted by allometry alone, indicating a change in wing shape. No statistically significant differences were found in the wing size/shape of An. gambiae s.s. or An. arabiensis. Conclusions The partial agreement between the tethered flight results and recent results based on aerial sampling of these species suggest a degree of discrimination between appetitive flyers and long-distance migrants although identifying HFAs as long-distance migrants is not recommended without further investigation.


2011 ◽  
Vol 36 (5) ◽  
pp. 547-549
Author(s):  
Ying-gang DU ◽  
Hai-bo XIA ◽  
Jia-hua CHEN ◽  
Qing-e JI

Genetics ◽  
2003 ◽  
Vol 163 (2) ◽  
pp. 823-831
Author(s):  
J A Sved ◽  
H Yu ◽  
B Dominiak ◽  
A S Gilchrist

Abstract Long-range dispersal of a species may involve either a single long-distance movement from a core population or spreading via unobserved intermediate populations. Where the new populations originate as small propagules, genetic drift may be extreme and gene frequency or assignment methods may not prove useful in determining the relation between the core population and outbreak samples. We describe computationally simple resampling methods for use in this situation to distinguish between the different modes of dispersal. First, estimates of heterozygosity can be used to test for direct sampling from the core population and to estimate the effective size of intermediate populations. Second, a test of sharing of alleles, particularly rare alleles, can show whether outbreaks are related to each other rather than arriving as independent samples from the core population. The shared-allele statistic also serves as a genetic distance measure that is appropriate for small samples. These methods were applied to data on a fruit fly pest species, Bactrocera tryoni, which is quarantined from some horticultural areas in Australia. We concluded that the outbreaks in the quarantine zone came from a heterogeneous set of genetically differentiated populations, possibly ones that overwinter in the vicinity of the quarantine zone.


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